Apparatus for controlling the drying operation in paper machines



Dec. 4, 1928. 1,694,349

' G. S. WITHAM, JR

APPARATUS FOR CONTROLLING THE DRYING OPERATION 1N PAPER MACHINES FiledApril 2, 1928 INVENTOR s. BY 5 2L Patented Dec. 4, 1928. i i

arssr'rr are,

GEORGE S. WITHAM, JR, OF HUDSON FALLSL'REW YORK.

APPARATUS FOR CONTROLLING THE DRYING OPERATION IN P APER MACHINES.

Application filed April 2, 1928. Serial No: 266,777. r

This invention relates to apparatus for ordinarily a large gap. In orderto close controlling the drying operation in paper this gap, a sealingmember 16 of any suitmachines and more in particular to apparaableflexible material is attached to the doctus for controlling the moisturecontent of tor 14 along its whole upper edge and so 60" the paper at acertain stage of its manufacdisposed as to ride against the feltroll,13,'

t as indicated. Vhile there are many mate- 'The in vention is closelyrelated to appararials available for the purpose of sealing the tus ofthe type disclosed in my- Patents gap, I prefer at. present rubberbelting or. 1,626,060,1,646,515 and 1,646,516 and has for the like. 65-

its general object a simplification of struc- To carry out the object oftheinvention,

t air is blowninto the collector space-referred For a full understandingof the invention, to, to thereby take up the moisture given offreference is made to the accompanying drawby the paper and themoisture-charged air i h i is then passed" to a moisture-responsive de-70 Fig. 1 is a fragmentary side view of apvice As indicated in dottedlines inFig. 3, paratus embodying the invention; a I an 1s preferablyprepared or conditioned in Fig. 2 is an enlarged view of parts shown aconditioning' apparatus 17 and then passed in Fig. 1; I by a blower 23or the like into the space men- I Fig. 3 is a sectional view taken online tioned. With the nozzle 18 is preferably asso- 20 3 3, Fig, 2,ciated aboard 19 for roughly sealing the Having reference to Fig. 1, 10are the dryspace adjacent to the nozzle against influx ing rolls of atypical installation consisting of air from the body of-air surroundingthe of two or more'rows of drying drums or cyl machine. It is notpractically possible and inders in super position. The web 11 of the notnecessary to entirely close off cornmuni 80 paper is carried around thedrying .cyllncation between the collector space and the ders 10 in theusual way and the felt roll outside, leakage of air into the collectorspace 1-2 with the-felt 13 passing over the drying being avoided byproducing a sufiicient posicylinders in superposition on the webofpative pressure at the nozzle end? per also constitutes part of ausual form of Into. the end of the collector space oppo- 85 36 papermachines. I j site to the nozzle 18, I place a. pipe 21 for In the spacebetween the drying cylinpassing a sampling stream of the moistureders10, below the felt roll 13 is disposed a charged air to a moisturesensitive element metal blade 14 generally referred to in the 22actuating an indicating device 24 or a trade as a doctor, the lower edgeof which. recording device or a regulating device as 90 is in intimatecontact with the roller cylinmay be desired. For practical reasons I der10. The doctor, which serves the emerprefer to produce a continuous flowof a gency purpose of loosening and lifting the sampling stream by meansof a suction blowweb of paper free from the cylinder is also er 23 la'st andard part of an equipment of this i The operation and itssignificance are as .95

40 type. i follows:

' The invention consists in an arrangement The paper manufactured ispassed over the whereby the parts referred toare utilized to dryingcylinders. The surface portion of form a collector box for directing agas or the web forming part-of the collectorspace .air into contact witha surface portion of the described has a definitely limited area. The100 web of paper, at the exclusion of the atmosamount of moisture givenoff in a unit of time "phere mormally surrounding the paper. by thischanging surface of constantarea is Having special reference to Figs. 2and 3," therefore a measure of the moisture content the space betweenthe doctor, the lower dryof the web of paper at the particular point ingcylinder 10, the web of paper 11 on the of travel, assuming that theother conditions 105 upper left-hand drying cylinder 10, the felt ofoperation are fairly constant. roll 12 and the felt 13 is converted intoa By preparing air of constant temperature collector box for the passageof air in conand constant relative humidity,i. e. of contact with theportion of the paper'web passstant properties as to temperature and hu-.

ing continuously past the space. As seen midity for passage through thecollector 110 from Fig. 2, between theupper edge of the space, themoisture content of the air pass doctor blade 14 and the felt roll thereis ing o'ut of'the latter is a reliable criterion tions in the moisturecontent can be indicated, recorded or otherwise utilized for the controlof the drying operation.

Provisions may be made to shield the collector space against the effectsof heat from the lower cylinder 10'or other parts other than the web,but I have found thatthese effects do not introduce any appreciableerrors, but on the other hand, have beneficial action in that they causea rise of the temperature of the air passing through the collector spaceand thereby reduce or even prevent condensation or sweating.

In some instances I find it desirable or even practically necessary toat least part-- ly close up the end of the space where the suctionnozzle 18 is located in order to obtain the proper amount of positivepressure in the collector space.

In the foregoing I have made reference only to air as a medium for theabsorption of moisture, and more in particular to conditioned air. It isunderstood the invention is not affected by the character of the gaseousmedium.

For the sake of brevity in the claims, the word doctor designates ablade so positioned in contact with a roll adjacent to the line at.which aweb of paper passing over the roll normally draws away from thelatter, as to immediately lift the paper from the roll in case the papershould stick to the roll beyond the normal line of separation.

I claim:

1. In apparatus of the character described, having two rows of dryingrolls in staggered relation, wherein a web of paper passes alternatelyover a roll of each row, a felt roll between adjoining rolls of one rowand opposite a roll of the other row and a doctor disposed between thefelt roll and the last mentioned roll and bearing on the latter, thecombination with the doctor, of a sheet of flexible material attached tothe doctor and bearing upon the felt roll, whereby the doctor and thesheet form a partition connectmg the felt roll and the drying roll uponwhich the doctor bears.

2. In apparatus of the character described,

having two rows of drying rolls in staggered relation, the combinationwith two adjoining rolls of one row, a felt roll disposed between theadjoining rolls carrying a belt for movement over the adjoining rolls,the drying roll of the other row, disposed intern'iediate the "saidadjoining rolls and a. doctor disposed between the felt roll and thesaid roll of the other row and bearing upon the latter, of a sheet offlexible material attached to the doctor and bearing upon the felt roll,whereby the doctor and the sheet form a partition substantiallycoextensive with the rolls.

3. In apparatus of the character described, having two rows of dryingrolls in staggered relation, wherein a web of paper passes alternatelyover a roll of each row, a felt roll between adjoining rolls of one rowcarrying a felt passing over said adjoining rolls, a doctor disposedbetween the felt roll and the adjacent roll of the other row bearingupon the latter, the combination with the doctor, of a sheet offlexible-material attached to the doctor and bearing upon the felt roll,whereby the doctor and the sheet form a partition connecting the feltroll and the drying roll upon which the latter bears, and defining withthe last mentioned drying roll, the felt on the felt roll and the web ofpaper a conduitfor a gas, means for passing a gas into one end of said'conduit and means for withdrawing gas from the other end of saidconduit.

4. In apparatus of the character described, having two rows of dryingrolls in staggered relation, wherein a web of paper passing alternatelyover rolls of the two rows, in con-- junction with the rolls definestrough-like spaces intermediate the ends of the latter, a felt rollerdisposed between two rolls of one row, carrying a felt passing overthe-two rolls and a doctor disposed between the felt roll and theopposite drying roll of the other row and bearing upon the latter, thecombination with the doctor, of a sheet of flexible material attached tothe latter and disposed to bear upon the felt roll, the doctor and thesheet forming apartition for separating the trough-like space into twosections and means for passing a gas through one of the said sections toabsorb moisture from the web of paper which forms a part of the conduit.

In testimony whereof I afiix my signature.

GEORGE S. WVITHAM, J n.

